966M XE and 972M XE Wheel Loaders Power Train, Steering, Braking, Hydraulic, and Machine Systems Caterpillar

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Sudden movement or accidental starting of the machine can cause personal injury or death to persons on or near the machine. To prevent personal injury or death, perform the following: Park the machine on a smooth, level surface. Lower the work tool to the ground and engage the parking brake. Stop the engine and remove the key. Block the wheels and install the steering frame lock.

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Personal injury or death can result from sudden movement of the lift cylinders or the tilt cylinders. Do not stand under the work tool when you are testing or adjusting the lift cylinders or the tilt cylinders. Do not stand under the lift arms when you are testing or adjusting the lift cylinders or the tilt cylinders.

Specifications

Note: The distances that are listed for drift in the tables are for a new machine.

Introduction

This test will check the drift rate of the lift cylinder. The drift rates will change according to many conditions (hydraulic oil temperature, type of work tool, or load on the work tool).

Test Preparation

1. Park the machine on a smooth, level surface.

2. Move the transmission direction control switch to the NEUTRAL position.

3. Lower the work tool to the ground and engage the parking brake.

4. Block the wheels and place the steering frame lock in the LOCKED position.

Test Procedure

Check The Lift Cylinder Drift

This test will check the drift rate of the lift cylinders. The drift rates will change according to many conditions (hydraulic oil temperature, type of bucket, load in the bucket.). The values in the table are for an empty bucket.

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Illustration 1	g03691704
(1) Manual lowering ball valve

1. Ensure that the ball valve (manual lower) (1) is in the CLOSED position.

   Note: The ball valve is located in the front frame near the articulation hitch.

2. Start the engine. Warm the hydraulic oil to normal operating temperature of approximately 49 to 65°C (120 to 150°F).

3. To check the lift circuit, raise the bucket to the maximum height and move the control lever to the HOLD position.

4. Turn the engine start switch to the OFF position.

5. Measure the distance of cylinder rod movement. Refer to Table 1 for the maximum distance.

6. If the amount of cylinder drift is within the specification, this lift circuit is not causing a drift problem.

7. If there is too much drift, check the anti-drift valve for the lift function and check the ride control balance spool. If replacement of lift cylinder is required, refer to Disassembly and Assembly, "Lift Cylinder - Remove and Install".

8. Start the engine. Lower the bucket to the ground. Turn the engine start switch to the OFF position.

Note: Auxiliary cylinders will drift in the CLOSE (LOWER) direction because of an orifice in the rod end line. The orifice connects to the tank.

Check The Tilt Cylinder Drift

This test will check the drift rate of the tilt cylinders. The drift rates will change according to many conditions (hydraulic oil temperature, type of bucket, load in the bucket). The values in the table are for an empty bucket.

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Illustration 2	g03691710
(1) Manual lowering ball valve

1. Ensure that the ball valve (manual lower) (1) is in the CLOSED position.

   Note: The ball valve is located in the front frame near the articulation hitch.

2. Start the engine. Warm the hydraulic oil to normal operating temperature of approximately 49 to 65°C (120 to 150°F).

3. Cycle the lift cylinders five times.

4. To check the tilt circuit, raise the bucket to the maximum height, and keep the bottom of the bucket parallel to the ground. Move the control lever to the HOLD position.

5. Turn the engine start switch to the OFF position.

6. Measure the distance of rod movement. Refer to Table 2 for the maximum distance.

7. If the amount of cylinder drift is within the specification, this tilt circuit is not causing a drift problem.

8. If there is too much drift, check the anti-drift valve for the tilt function and check the tilt back line relief valves. If replacement of tilt cylinder is required, refer to Disassembly and Assembly, "Tilt Cylinder - Remove and Install".

9. Start the engine. Lower the bucket to the ground. Turn the engine start switch to the OFF position.

Note: Auxiliary cylinders will drift in the CLOSE (LOWER) direction because of an orifice in the rod end line. The orifice connects to the tank.